1. Field of the Invention
The present invention relates to a metallic decorative sheet used for home electric appliances or the like and a production method thereof, and a production method of an insert molded body using the metallic decorative sheet.
2. Description of the Related Art
Conventionally, a molded body formed by coating a metallic decorative sheet (having a quality like metal) on a thermoplastic resin molded body used for home electric appliances has been known. The molded body is produced according to an insert molding method by disposing preliminarily the metallic decorative sheet in a die and injecting thermoplastic resin for forming the thermoplastic resin molded body into the die.
The molded body is commonly used in a display portion, a touch panel or the like of home electric appliances, thus, a back surface of the metallic decorative sheet is partially printed with a design of words, graphics or the like in non-metallic ink, and the entire back surface except the words and/or graphics is vapor deposited or sputtered with metallic ink.
As a production method of the metallic decorative sheet, there has been disclosed one in Japanese Patent Laid-open No. 2005-288720. As illustrated in FIG. 4, the production method comprises steps of printing on one surface of a transparent thermoplastic resin film 10 a design 130 to be displayed on an outer surface thereof, vapor depositing thereon a metal thin-film layer 112, subsequently printing an ink layer 114 to preventing the metal thin-film layer from being seen, and finally printing a binder layer 115 for binding with a thermoplastic resin molded body 120.
However, as illustrated in FIG. 4, when the thermoplastic resin molded body 120 is coated by the metallic decorative sheet 110 according to the insert molding method, there is a problem that a part of the metal thin-film layer 112 exposed in an edge region K of the metallic decorative sheet 110 may have a contact with the thermoplastic resin molded body 120.
Consequently, it would be difficult for the exposed part of the metal thin-film layer 112 to contact closely with the thermoplastic resin molded body 120; if adhered by an alkaline solution such as a bleaching agent or the like, the metal thin-film layer 112 would be dissolved (corroded) easily by the alkaline solution. Thereby, the metallic decorative sheet 110 detaches from the thermoplastic resin molded body 120 in the edge region K, which deteriorates the visual appearance of the product.